As impeachment moves into its next phase, House Democrats lack testimony from major players in the Trump administration about allegations that the president withheld military aid and a coveted White House meeting to pressure Ukraine into investigating his domestic political rivals.


Why it matters: House Democrats have cited the White House's blanket refusal to cooperate with the impeachment inquiry as evidence of obstruction for a potential article of impeachment.
- At the House Judiciary Committee's first impeachment hearing on Wednesday, Democrats displayed a sign in which "obstruction of Congress" was listed as one of three impeachable offenses they say Trump has committed.
- One of the main Republican criticisms of the inquiry has been that many of the witnesses do not have firsthand knowledge of Trump's decision-making and have relied on "hearsay" evidence. Many of those who would have that knowledge, however, have been blocked by the administration from testifying.
The key missing witnesses
- Acting White House Chief of Staff Mick Mulvaney said at a press conference in October that Trump froze military aid until Ukraine agreed to investigate a conspiracy theory about the DNC server hacked by Russia in 2016 — before walking the comments back entirely.
- Former national security adviser John Bolton was “personally involved in many of the events” at the heart of the impeachment inquiry, according to a letter from his attorney. He told former Russia adviser Fiona Hill to alert White House lawyers about a possible Ukraine quid pro quo, calling it a "drug deal" cooked up by Mulvaney, Rudy Giuliani and EU Ambassador Gordon Sondland.
- Secretary of State Mike Pompeo and Vice President Mike Pence were both "in the loop" about efforts to pressure Ukraine to announce the investigations, Sondland testified. "It was no secret," he added.
- Giuliani has said he kept Trump apprised of his efforts in Ukraine, and multiple witnesses believe that he spoke for the president when it came to Ukraine matters. Call records obtained by the House Intelligence Committee show that Giuliani was on the phone with the White House more than a dozen times on the day that Trump forced out former Ambassador to Ukraine Marie Yovanovitch.
Between the lines: House Democrats won a major victory last month when a federal judge rejected the White House's claims that its aides are "absolutely immune" from congressional subpoenas.
- The case is being appealed, however, and Democrats have stated that they have no intention of allowing the Trump administration to delay the impeachment process for months in court.
Driving the news: Law professor Jonathan Turley, the only witness invited by Republicans to testify on Wednesday, warned House Democrats that they would "leave half the country behind" if they rushed impeachment.
- Turley argued that the House should wait for the courts to decide if key witnesses, like Pompeo, Mulvaney and Bolton, should testify.
- Trump, meanwhile, said on Tuesday he would be open to those same officials testifying in the Republican-controlled Senate, where he said they'll "get a fair trial."
Editor's note: The graphic has been updated to reflect that Katie Wheelbarger did cooperate with the impeachment inquiry, but investigators decided they did not need her testimony.
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